The present invention relates to a bar feeding machine for a lathe. More particularly, the present invention relates to an improved feeding machine which remains in alignment and in a stable condition as it feeds bar stock to be machined.
Conventional bar feeding machines typically comprise one or more tubular members for maintaining bar stock at high speeds of rotation therein as the bar stock is advanced toward the lathe. A problem associated with use of such machines is that it is difficult to maintain such high rotational speeds of the bar stock within the tubular members without causing excessive noise and vibration of the machine as a result of the high speed of rotation and resulting thermal growth of the tubular members. In addition, it is difficult to maintain the bar stock in proper alignment with the lathe.
Although there have been a number of proposals to alleviate the above problems, heretofore none have been widely accepted. For example, in U.S. Pat. Nos. 5,146,819 and 4,889,024, there is disclosed a cylindrical stabilizing body having a length at least equal to the length of the bars to be machined. The cylindrical body includes a peripheral ring connected by reinforcing ribs to each of a plurality of tubular cavities, each enclosing a respective one of a plurality of tubular members. Each of the tubular cavities are further connected by reinforcing ribs to adjacent tubular cavities. It is disclosed that this cylindrical body is normally made from extruded aluminum and can also be made from a synthetic material. However, because the cylindrical body extends substantially along the entire length of the tubular members, it is very expensive. In addition, the desired stability of the tubular members is not properly achieved.
Thus, there exists a need for a bar feeding assembly which is relatively inexpensive to manufacture, and which permits thermal growth of the tubular members in the axial direction while providing adequate stiffness in the axial and radial directions.